Abstract

Chemical and cytotoxic studies were carried out on two plant species, Caiophyllum
mucigerum (Guttiferae) and Ploiarium alternifolium (Theaceae). The chemical
investigations covered anthraquinones, triterpenes, xanthone and coumarins. These
compounds were isolated using common chromatographic techniques and HPLC
and identified using spectroscopic methods including 2-D NMR, GCMS, MS, IR
andUV.
Ploiarium alternifolium provided emodin, ploiariquinone A, 1,8-dihydroxy-3-
methyl-6-methoxy-anthraquinone, 3 β-benzoyloxyolean-ll-en-13β,28-olide and
euxanmodin C. Emodin and 1, 8-dihydroxy-3-metbyl-6-methoxy-antbraquinone have
not been reported from Ploairium aiternifolium. Calophyllum mucigerum gave the
common steroidal triterpenes friedelin and stigmasterol, a prenylated xanthone
cudraxanthone C and two new coumarins mucigerin I and mucigerin II. The crude n-hexane, ethyl acetate and ethanol stem bark extracts of both plants were
screened for their larvicidal activity against the larvae of Aedes aegypti. The crude
n-hexane, ethyl acetate and ethanol extracts for both of the plants were susceptible to
the larvae of Aedes aegypti with LC₅₀ values of 95.0 µg/ml, 129.4 µg/ml and 131.6
µg/ml, respectively for Ploiarium alternifolium whereas 87.9 µg/ml, 138.5 µg/ml
and 147.4 µg/ml, respectively for Calophyllum mucigerum. Larvicidal activity on
the pure compound, emodin gave an LCso value of 2.79 µg/ml.
The cytotoxicity, antibacterial and antifungal activities test were also carried out on
the three crude extracts of both plants and also on the pure compounds.
Cytotoxicities were determined by performing the microtitration assay. All the crude
extracts were weakly cytotoxic towards the CEM-SS cell line except hexane extracts
from C. mucigerum and P. alternifolium which gave moderate activity with IC₅₀ =
16.2 µg/ml and lC₅₀ = 19.2 µg/ml, respectively. The pure compound euxanmodin C
was the most sensitive against the cell line with IC₅₀ = 5.9 µg/ml. The antimicrobial
activity was tested using the modified disc diffusion method. The crude extracts
from both plants also showed different antimicrobial activity against the growth of
four bacteria; Bacillus subtiUs mutant, Bacillus subtilis wild type, Staphyloccus
aures and Pseudomonas aeruginosa. However, these crude extracts were weakly
active against the bacteria with less than 10 mm diameter inhibition zone.